Expression study of cadherin7 and cadherin20 in the embryonic and adult rat central nervous system

<p>Abstract</p> <p>Background</p> <p>Vertebrate classic cadherins are divided into type I and type II subtypes, which are individually expressed in brain subdivisions (e.g., prosomeres, rhombomeres, and progenitor domains) and in specific neuronal circuits in region-specific manners. We reported previously the expression of <it>cadherin19 </it>(<it>cad19</it>) in Schwann cell precursors. <it>Cad19 </it>is a type II classic cadherin closely clustered on a chromosome with <it>cad7 </it>and <it>cad20</it>. The expression patterns of <it>cad7 </it>and <it>cad20 </it>have been reported previously in chick embryo but not in the developing and adult central nervous system of mammals. In this study, we identified rat <it>cad7 </it>and <it>cad20 </it>and analyzed their expression patterns in embryonic and adult rat brains.</p> <p>Results</p> <p>Rat cad7 protein showed 92% similarity to chick cad7, while rat cad20 protein had 76% similarity to <it>Xenopus </it>F-cadherin. Rat <it>cad7 </it>mRNA was initially expressed in the anterior neural plate including presumptive forebrain and midbrain regions, and then accumulated in cells of the dorsal neural tube and in rhombomere boundary cells of the hindbrain. Expression of rat <it>cad20 </it>mRNA was specifically localized in the anterior neural region and rhombomere 2 in the early neural plate, and later in longitudinally defined ventral cells of the hindbrain. The expression boundaries of <it>cad7 </it>and <it>cad20 </it>corresponded to those of region-specific transcription factors such as <it>Six3</it>, <it>Irx3 </it>and <it>Otx2 </it>in the neural plate, and <it>Dbx2 </it>and <it>Gsh1 </it>in the hindbrain. At later stages, the expression of <it>cad7 </it>and <it>cad20 </it>disappeared from neuroepithelial cells in the hindbrain, and was almost restricted to postmitotic cells, e.g. somatic motor neurons and precerebellar neurons. These results emphasized the diversity of <it>cad7 </it>and <it>cad20 </it>expression patterns in different vertebrate species, i.e. birds and rodents.</p> <p>Conclusion</p> <p>Taken together, our findings suggest that the expression of <it>cad7 </it>and <it>cad20 </it>demarcates the compartments, boundaries, progenitor domains, specific nuclei and specific neural circuits during mammalian brain development.</p

Stabilization of ATF4 protein is required for the regulation of epithelial–mesenchymal transition of the avian neural crest

AbstractEpithelial–mesenchymal transition (EMT) permits neural crest cells to delaminate from the epithelial ectoderm and to migrate extensively in the embryonic environment. In this study, we have identified ATF4, a basic-leucine-zipper transcription factor, as one of the neural crest EMT regulators. Although ATF4 alone was not sufficient to drive the formation of migratory neural crest cells, ATF4 cooperated with Sox9 to induce neural crest EMT by controlling the expression of cell–cell and cell–extracellular matrix adhesion molecules. This was likely, at least in part, by inducing the expression of Foxd3, which encodes another neural crest transcription factor. We also found that the ATF4 protein level was strictly regulated by proteasomal degradation and p300-mediated stabilization, allowing ATF4 protein to accumulate in the nuclei of neural crest cells undergoing EMT. Thus, our results emphasize the importance of the regulation of protein stability in the neural crest EMT

Some stackelberg type location game

AbstractThis paper considers a Stackelberg type location game over the unit square [0,1] × [0,1]. There are two chain stores, Players I and II, which sell the same kind of articles. Each store is planning to open a branch in region [0,1]. The purpose of each store is to decide the location to open its branch. In such a situation, the demand points, i.e., the customers, distribute continuously over [0,1] in accordance with cdf G(·). Each customer wants to buy at a closer store between them, but never moves more than a distance ℓ. We also assume that Player I is forced to behave as the leader of this game and the opponent (Player II) is to be the follower. It is shown that there are various types of Stackelberg equilibriums according to the conditions of G(·) and ℓ

Modularization for the Cell Ontology

One of the premises of the OBO Foundry is that development of an orthogonal set of ontologies will increase domain expert contributions and logical interoperability, and decrease maintenance workload. For these reasons, the Cell Ontology (CL) is being re-engineered. This process requires the extraction of sub-modules from existing OBO ontologies, which presents a number of practical engineering challenges. These extracted modules may be intended to cover a narrow or a broad set of species. In addition, applications and resources that make use of the Cell Ontology have particular modularization requirements, such as the ability to extract custom subsets or unions of the Cell Ontology with other OBO ontologies. These extracted modules may be intended to cover a narrow or a broad set of species, which presents unique complications.&#xd;&#xa;&#xd;&#xa;We discuss some of these requirements, and present our progress towards a customizable simple-to-use modularization tool that leverages existing OWL-based tools and opens up their use for the CL and other ontologies

Three-dimensional arrangement of F-actin in the contractile ring of fission yeast

The contractile ring, which is required for cytokinesis in animal and yeast cells, consists mainly of actin filaments. Here, we investigate the directionality of the filaments in fission yeast using myosin S1 decoration and electron microscopy. The contractile ring is composed of around 1,000 to 2,000 filaments each around 0.6 μm in length. During the early stages of cytokinesis, the ring consists of two semicircular populations of parallel filaments of opposite directionality. At later stages, before contraction, the ring filaments show mixed directionality. We consider that the ring is initially assembled from a single site in the division plane and that filaments subsequently rearrange before contraction initiates